Heterogenically catalysed gas-phase partial oxidation method for precursor compounds of (meth)acrylic acid

Abstract

The invention relates to a method for the heterogenically catalyed gas-phase partial oxidation of precursor compounds of (meth)acrylic acid in a fixed catalyst bed, containing as the catalyst an activated mass of mixed oxide, shaped to form a geometric body. Said geometric body is a geometric base body, into whose surface a cavity is incorporated.

1. A mixed oxide active material having a geometric body, wherein the geometric body is a geometric base body having at least one cavity,
 wherein the ratio of the volume of the geometric body V B  to the geometric base body V BA ≦0.63 and the ratio of the external surface area of the geometric body A B  to V B ≧22 cm −1 , and 
 wherein the mixed oxide active material comprises at least one set of elements selected from the group of sets consisting of 
 a) the elements Mo, Cu and P; 
 b) the elements Mo, Bi and Fe; 
 c) the elements Mo, V and W; and 
 d) the elements Mo, V, Te and Nb. 
 
     
     
       2. The mixed oxide active material of  claim 1 , wherein the A B  to V B  ratio is ≧23 cm −1 . 
     
     
       3. The mixed oxide active material of  claim 1 , wherein the A B  to V B  ratio is 24 cm −1 . 
     
     
       4. The mixed oxide active material of  claim 1 , wherein the A B  to V B  ratio is ≧25 cm −1 . 
     
     
       5. The mixed oxide active material of  claim 1 , wherein the A B  to V B  ratio is ≧26 cm −1 . 
     
     
       6. The mixed oxide active material of  claim 1 , wherein the A B  to V B  ratio is ≧27 cm −1 . 
     
     
       7. The mixed oxide active material of  claim 1 , wherein the A B  to V B  ratio is from 22 cm −1  to 30 cm −1 . 
     
     
       8. The mixed oxide active material of  claim 1 , wherein the V B  to V BA  ratio is ≦0.60. 
     
     
       9. The mixed oxide active material of  claim 1 , wherein the V B  to V BA  ratio is ≦0.50. 
     
     
       10. The mixed oxide active material of  claim 1 , wherein the V B  to V BA  ratio is ≦0.45. 
     
     
       11. The mixed oxide active material of  claim 1 , wherein the V B  to V BA  ratio is from 0.40 to 0.60. 
     
     
       12. The mixed oxide active material of  claim 1 , wherein the A B  to V B  ratio is ≧26 cm −1  and the V B  to V BA  ratio is ≦0.45. 
     
     
       13. The mixed oxide active material of  claim 1 , wherein the geometric base body is a shape selected from the group consisting of a cylinder, a pyramid, a cone, a cube, a right parallelepiped, a prism, a sphere, a truncated cone, and a truncated pyramid. 
     
     
       14. The mixed oxide active material of  claim 1 , wherein the geometric body is in the shape of a ring. 
     
     
       15. The mixed oxide active material of  claim 1 , wherein the geometric body has an annular geometry having a diameter of from 5.5 mm to 7 mm, a height of 3 mm, and an internal diameter of from 3.5 to 5 mm.